The prior art has provided many designs for key rings that retain one or more keys on a key holder that is connected to a housing. An example of a prior art key ring is disclosed in Nadel, U.S. Pat. No. 3,597,951. Nadel utilizes a hook-like element having an external gapped, ring portion and an internal elongated shank portion that extends into a housing and also, into the coils of a spring located within the housing. The ring portion, which forms the key holder, is configured to pass through the retaining holes of the keys.The spring biases the ring portion to retract into an inverted, saddle-like seat that is located at one end of the housing.The base of the saddle, which has an opening for the passage of the shank portion, acts as an abutment, to limit the inward travel of the ring portion. The sidewalls of the saddle enclose a gap, that is defined in the ring portion, to prevent the keys from being removed through the gap when the ring portion is retracted within the seat. When the ring portion is pulled away from the housing, the gap is exposed to permit the keys to be removed from and to be mounted on the ring portion.
Other key rings of the prior art are double ended, that is, they employ a pair of key holders that are located at the opposite ends of a central housing. The advantages of such key rings over a key ring having a single key holder are manifest. For instance, the key carrying capacity of the key ring is increased by providing a pair of key holders. Additionally, keys may be segregated, yet retained on a single device. For example, automobile keys may be mounted on one of the key holders and house keys may be mounted on the other of the key holders to reduce the amount of fumbling that one normally goes through when trying to locate the desired key. Furthermore, such double ended key rings permit a key to be mounted on one of the key holders and an identifying tag for the key to be mounted on the other of the key holders.
A typical example of a prior art double ended key ring is Bridwell, U.S. Pat. No. 2,916,907. Bridwell employs a pair of gapped, loop-like members, that form the key holders. The loop-like members are located at the opposite ends of a tube, that forms a central housing, and are connected to one another and are biased against the ends of the tube by a spring located within the tube. In Bridwell, the annular end surfaces of the tube, form seats for the loop-like members that provide an abutment to limit the degree of inward travel of loop-like members. The transverse cross-section of the tube, and hence, the annular end surfaces, is sized so that when the loop-like members bear against the end surfaces, the gaps in the loop-like members are enclosed within the tube to prevent the removal of the keys from the loop-like members.
Bridwell is simply and inexpensively assembled by inserting the biasing spring into the tube, stretching the biasing spring past the ends of the tube, and then, connecting the key holders to the spring. The problem with the key ring design of Bridwell is that when one sights into the tube, the biasing spring is visible. The visibility of the biasing spring from the exterior of the housing can be aesthetically undesirable.
When the biasing mechanism is sought to be hidden within the housing, the key ring must employ an elongated portion or rod-like member, such as disclosed in Nadel, that slideably projects into a narrow opening of the housing and then into the coils of a biasing spring that is located within the housing. However, if the teachings of Nadel are applied to the double ended key ring of Bridwell, the result is a passageway, located within a housing, having narrow openings at its opposite ends that are too small to permit the entry of a biasing spring, let alone to permit the connection of the rod-like members to the biasing spring. This problem of design and assembly is solved in Zangrilli, U.S. Pat. No. 1,460,998. Zangrilli, discloses a pair of biasing mechanisms that are completely enclosed within the passageway of a tube-like housing. In order to solve the problem of assembling the biasing mechanisms within the passageway of the tube, a pair of spring loaded rods (forming the biasing mechanism) are inserted through openings located in a pair of endwalls. The endwalls are then brazed or welded to the ends of the tube. It should be pointed out that Zangrilli does not disclose that its biasing mechanism could be used in a key ring design. In this regard, the brazed or welded endwall construction of Zangrilli is not desirable for key rings because such fabrication would increase the unit cost of the key ring to an unacceptable level.
The present invention provides a double ended key ring in which a pair of key holders are located at the ends of a central housing. The central housing has a pair of seats for the key holders located at its ends. In a preferred embodiment, the seats comprise a pair of grooves and a pair of arcuate abutment surfaces that form the bottom of the grooves. A central passageway communicates between the abutment surfaces, and includes, a shoulder having a inner facing surface and a primary bore communicating between the inner facing surface and one of the abutment surfaces. In order to facilitate the assembly of the key ring, a cartridge-like bushing is provided that is operable to be located within the other end of the passageway. The bushing includes an endwall having a narrow opening. In a preferred embodiment, a pair of first and second lock pins respectively project, at one end, from the primary bore and the opening of the bushing, and are connected to the key holders. The lock pins respectively engage a pair of first and second biasing springs that respectively bear against the inner facing surface and the endwall of the bushing.
The use of the bushing solves the problem of inexpensively and simply assembling a double ended key ring by allowing one end of the passageway to remain open during assembly. In a preferred embodiment, one of the key holders and its associated first lock pin and first biasing spring are assembled in the end of the passageway having the primary bore and then, the bushing, the other key holder and its associated second lock pin and second biasing spring are assembled, as a subassembly, that is in turn inserted into the other end of the passageway. The bushing and the passageway may be sized for a force fitting connection to do away with the need for the prohibitively expensive welded or brazed construction that is provided for in Zangrilli.
In addition to the inexpensive and relatively simple assembly techniques, the present invention by preferably employing a pair of biasing springs, provides independent biasing forces to the key holders that can be preselected in accordance with the key carrying capacity of the key holders. Thus, one key holder can be made larger than the other key holder to carry more keys and its associated biasing spring can be designed to provide a greater biasing force than the other of the biasing springs. In this regard, the single biasing spring of Bridwell, necessarily, only provides a single biasing force to the loop-like members and as a result, the loop-like members are equally sized to have an equal key carrying capacity.